Treatment of keratin fibers

ABSTRACT

The set stability of keratin fibers, particularly wool fibers, is improved by polymerizing a halogen-containing vinyl or acrylic compound in the fibers and thereafter reacting the deposited polymer with a thiosulfate. Polymerization of the vinyl or acrylic compound can be readily effected in the presence of persulfuric acid and a tetrakis-(hydroxymethyl)-phosphonium salt.

United States Patent 11 1 Wolfram TREATMENT OF KERATIN FIBERS [75]Inventor: Leszek J. Wolfram, Rockville, Md.

[73 Assignee: I.W.S. Nominee Company Limited,

London, England f 22 Filed: July 12, 1971 21 Appl. No.: 161,978

[52] US. Cl 8/115.6, 8/127.5, 8/127.6, 8/128 R, 8/128 A, 117/141 [51]Int. Cl D06m 13/00 [58] Field of Search 8/127.6, 128 R, 128 A, I8/127.5, 115.6; 117/141 [56] References Cited UN ITEDSTATES PATENTS3,589,856 6/1971 Wolfram..... s 127.5

3,644,084 v 2/1972 l-lsiung et al [111 3,801,271 [451 -Apr.'2, 1974OTHER PUBLICATIONS Wolfram et 211., American Dyestuff Reporter, Feb. 13,1967, pages 31-37.

Primary ExaminerLeon D. Rosdol Assistant Examiner-H. Wolman Attorney,Agent, or Firm-Stowell & Stowell [57] ABSTRACT The set stability ofkeratin fibers, particularly wool fibers, is improved by polymerizing ahalogencontaining vinyl or acrylic compound in the fibers and thereafterreacting the deposited polymer with a thiosulfate. Polymerization of thevinyl or acrylic compound can be readily effected in the presence ofpersulfuric acid and a tetrakis-(hydroxymethyl)- phosphoniurn salt.

7 Claims, No Drawings TREATMENT OF KERATIN FIBERS The invention relatesto a method for improving the set stability of keratin fibers, such aswool'and hair and of yarns and fabrics comprising such fibers and tonovel compositions for carrying out the method.

I have found that the set stability of keratin fibers, for example, thestability of curls in fibers, threads and yarns, and creases'in fabricsand garments containing keratin fibers, when subjected to wetting can besubstantially improved by polymerizing a halogencontaining vinyl oracrylic compound possessing a labile halogen atom in the fibers eitherin loose form or in the form of yarn or fabrics and thereafter reactingthe deposited polymer with a thiosulfate whereby the halogen isreplaced, at least in part, by thiosulfato groups, thereby formingso-called Bunte salt compounds (H. Bunte, Berichte, 7, 646, 1874).

Examples of labile halogen containing monomers suitable for the practiceof this invention are vinyl chloroacetate, chloromethylstyrene,chloromethyl acrylate, bromoethyl methacrylate, N-(2-chloroethyl)methacrylamide.

The polymerization of the halogen-containing vinyl or acrylic compoundin the fiber is advantageously carried out under acid conditions,preferably at a pH of 1.5 to 3.5, in the presence of a peroxide catalystsuch as persulfuric acid and an oxygen scavenger such astetrakis-(hydroxymethyl)-phosphonium chloride. (L. J. Wolfram and .l.Menkart, Amer. Dyestuff Rep., 56, 31, 1967) Dispersion of the vinyl oracrylic monomer in aqueous treating composition is facilitated bydissolving the monomer in a water-miscible organic solvent such asethanol and admixing the solution with an acidified aqueous solutioncontaining'polymerization initiating persulfate. In general,.thepolymerization, as measured by the increase in weight of the fibersimmersed in the solution, takes place at moderate rates at normalambient temperatures.

After termination of the polymerization by removal of the fibers andrinsing with water, thepolymers in the fibers are converted to Buntesalt derivatives by immersion of the fibers in a solution of athiosulfate in a suitable solvent, for example water orN,N-dimethylformamide.

The reaction scheme involving the displacement of halogen from polymersor copolymers by thiosulfate to yield the Bunte salt residues isillustrated by the example of vinyl chloroacetate in the followingequation:

In the case of poly-(vinyl chloroacetate), complete displacement wouldresult in a doubling of the molecular weight of the polymer; in the caseof polymercontaining wool, an increase in weight occurs followingthiosulfate treatment. In addition to measuring the increase in weightobtained, the efficiency of the displacement step can also be monitoredby hydrolyzing 2 the treated wool and determining the increase in itsthiol content.

Based on measurements of both the weight changes of treated wool and itsBunte salt content, the displacement reaction can go to 85 percentcompletion. This level of Bunte salt residues can be attained within 2hours at C. or in little-over 30 minutes at the boil.

The most perceptible change in the properties of the polymer-containingwool after thiosulfate displacement containing wool shows remarkableimprovement in its settability, and in the stability of the impartedset, for example, crimp, crease, pleat, or flat state. This beneficialeffect is noted at levels as low as 0.25 m M/g of wool treated.

Bunte salts are known to react with mercaptans to form disulfides. Buntesalt polymer-containing wool also reacts very readily with mercaptans;the reaction is accompanied by a drastic decrease in swelling of thewool and substantial lowering of overall sulfur content. The reactionresults in extensive cross-linking of the polymer with itself and to acertain extent with cysteine residues present in the keratin moiety ofthe wool. Such cross-linking produces a stabilization or setting of thefibers,.yarn or fabric in the'configuration in which it wasdone;permanent crimping, flat setting, creasing or pleatingis therebyaccomplished.

The principle of the invention and some of the variations in itsapplication are illustrated in the following examples:

A worstedflannel weighing 5.2 oz/sq. yard (Testfab rics lnc., New York,Style 503A) was used as the test fabric. Samples of the flannel werepurifiedby washing with 0.1 percent Triton X-lOO followed by rinsing indeionized water. The fabric was then centrifuged and conditioned 'at 65percent RHv and 222C. Detergent- .w'ashed New Zealand carpet wool wasused as the test fibers. I l V Bunte salts hydrolyze to yield sulfuricacid and the corresponding mercaptans on treatment with hot acids. Thisfeature was utilized in the analysis of the deposited polymer.Approximately 0.1 g of polymer-containing wool was hydrolyzed in .15 mlof 25 percent (vol/vol) H for 2 hours at 105C. After cooling, thesolution was made up to ml with deionized water, five milliliteraliquots were then withdrawn, madealkaline by addition of sodiumcarbonate and the mercaptan in them was titrated with salyrganic acidusing sodium nitroprusside as the indicator. I

The liquid retention technique, as described by Valko et al., J. Soc.Cosmetic Chemists, 3, 2 (1952) was used to determine the swelling ofpolymercontaining wool. Samples of wool (0.2-O.5 g) were im- 7 Testcreases were made parallel to the warp on a Hoffman press at 80 lbs.line steam pressure. The

I thioglycolic acid adjusted to pH 9.2 with ammonia. The

sprayed swatch was then creased on the press by a 30 second steam 30second bake cycle.

The creased samples were allowed to rest overnight in the laboratoryatmosphere, with the crease closed, prior to relaxation. Then they wereexposed to two levels of relaxation, cold and hot.

a. Cold relaxation. The swatches, open and with crease vertical, weresuspended in a deep beaker of water (0.1 percent Triton X-lOO) at C;each sample was held by two binder clips which were attached to a glassrod. After minutes the samples were withdrawn, dried by towel blottingand exposed to 65% RH, 70F for at least 16 hours prior to assessment.

b. Hot relaxation. A procedure identical to that in cold relaxation wasfollowed, except for the water temperature which was maintained at 60C.

The relaxed creases were evaluated at 65% RH and with a standard obliqueillumination. They were rated TABLE I EFFECT OF TIME ON THEPOLYMERIZATION OF VINYL CHLOROACETATE IN WOOL AT 30C Time ofPolymerization Polymer Add-on (l%) (min) Wool Fibers Wool Fabric 30 4.560 6.8 5.7 I20 9.9 8.7 I80 12.5 I06 240 4 5 360 l9.l

The chemical analysis for Bunte salt content was car- 5 ried out byhydrolysis and salyrganic acid titration (Table II).

TABLE 1! EFFECT OF TIME AND TEMPERATURE ON FORMATION OF BUNTE SALTRESIDUES IN POLYMER-CONTAINING WOOL Control experiment on untreated woolflannel on a scale 5 'perfect creaseflob 5 no crease, with the aid ofthree standards representing the 5, 3, and l levels on the scale.

The setting of single fibers was performed on stainless steel settingframes as described by Speakman, J. Soc. Dyers Colorists 52, 423 (1936).

The general procedure used for the deposition of polymer derived fromvinyl chloroacetate in wool fihers and wool fabric was as follows: themonomer, previously distilled to remove inhibitor (5g), was dissolved incc of absolute ethanol and to this solution was added with stirring 50cc of 0.02N H 80, containing 0.6% (NH S O and 0.6% THPC. The solutionwas placed in a conical flask, a 2 g'sample of wool was introduced, theflask was stoppered and kept for the required time in a constanttemperature bath at 30C. At the end of the reaction time the wool wasremoved from the flask, rinsed for at least 15 minutes in running tapwater, blotted, equilibrated in the conditioning room and weighed. Thepolymer add-on was expressed as the weight increase (in percent) of theconditioned untreated wool sample. Table I gives the results obtained atdifferent deposition times.

i Abrief study was made of the swelling properties of the Bunte saltpolymer-containing wool as afunction of pH. The results are presented inthe form of liquid retention values in Table III.

TABLE!!! EFFECT OF pH ON SWELLING OF BUNTE SALT POLYMER-CONTAINING WOOL(BUNTE SALT CONTENT 0.94 meqlg) pH Liquid Retention 54.5 56.1 S6.l 64.589.l 92.0

OQI AN- TABLE IV EFFECT OF TIME OF THIOSULFATF. TREATMENT ON THESWELLlNG OF WOOL AT pH 7 Liquid Retention Time of Treatment (at theboil) Polymer Containing Untreated (min) Wool Wool ine.

TABLE V LlOUlD RETENTION OF BUNTF. SALT POLYMER-CONTAINING WOOL AFTER'NEUTRALIZING WITH CYSTEINE pH Liquid Retention Swatches of flannel werecreased in the, Hoffman press, relaxed in cold and hot water and rated.The results are given in Table VI.

The improvement in set stability imparted to wool by deposit of theBunte salt polymer is clearly perceptible even at low values of add-on.

It was observed that creased swatches of untreated wool exhibited somewrinkling, edge rolling and unravelling on wetting and air drying. lnstriking contrast Bunte salt polymer-containing wool was smooth, flatand ravel-free.

Wool fibers of different add-on levels of Bunte salt polymer weremounted on setting frames, extended in water to 140 percent of theiroriginal length and transferred to 0.05N cysteine in pH 8 buffer at 25C.After minutes the frames were removed,.the fibers rinsed with water for1 minute, released and relaxed indeionized water at 35C for 10 minutes,1 hour, and 24 hours. At each time interval the fibers were removed fromwater, dried and their length measured. The obtained results are givenin Table VI].

TABLE Vll Set Retained After Wool 10 min 1 hr. 24 hrs Untreated 2.] nilnil Containing l4% of poly (vinyl ehloroacetate) 5.2 0.2 nil Containing5% Bunte salt polymer 22.6 l2.0 8.5 Containing 9% Bunte salt polymer27.0 17.5 12.4 Containing 12% Bunte salt polymer 27.9 l9.2 16.8

The general procedure used for the deposition of polymer derived fromN-(2-chloroethyl) methacrylamide in wool fibers and wool fabrics was asfollows: 2 g of monomer was dissolved in-25 cc of absolute ethanol(dioxane or methanol can be used instead), and to this solution wasadded with stirring 25 cc of 0.2N H containing 0.6% (NH S O and 0.3%THPC. The solution was placed in a conical flask, a 2 g sample of woolwas introduced, the flask was stoppered and maintained at 25C. After 30minutes 0.1 cc of percent thioglycolic acid was introduced, and thereaction M allowed to continue for a further 60 minutes. After thistime, the wool was removed from the flask, rinsed thoroughly with water,blotted and air dried. The weight increase recorded on drying indicateda polymer deposit of 26.5 percent. 1

Two general procedures for preparing the Bunte salt derivative of thispolymer are as follows: 7 1

a. Asample of the polymer-containing W00] (1 g) was immersed in 50 cc ofO.lN Na S O in 50 percent aqueous ethanol at 70C for 30 minutes, rinsedand dried. A determination of the Bunte salt content of the treated woolyielded a value of 0.75 mM/g.

b. A sample of thepolymer-containing wool (l g) was immersed in '50 ccof a O.lN MgS O solution in dimethyl formamide at 50C for 15 minutes,rinsed and dried. The Bunte salt content of this product was 0,85 mM/g.I

Other variations in the method of the invention will suggest themselvesto those skilled in the art and the invention is as claimed. 1

1. Method of treating keratinous fibers which comprises polymerizing inthe fibers a vinyl or acrylic monomer possessing a labile halogen atomto deposit in the fibers a polymer containing the labile halogen atomand thereafter reacting the deposited polymer with a thiosulfate toreplace the labilehalogen atoms with Bunte salt radicals. j v

2. Method of treating keratinous fibers as defined in claim 1 whereinthevinyl compound is vinyl ehloroacetate.

3. Method of treating keratinous fibers as defined in claim 1 whereinthe acrylic 7 compound is N-(2- chloroethyl) methacrylamide.

4. Method of treating keratinous fibers as defined in claim 1 whereinthe polymerization of the vinyl compound is effected under acidconditions in the presence of a peroxide catalyst and a scavenger foroxygen.

5. Method of treating keratinous fibers as defined in claim 1 whereinthe deposited and thiosulfate reacted

2. Method of treating keratinous fibers as defined in claim 1 whereinthe vinyl compound is vinyl chloroacetate.
 3. Method of treatingkeratinous fibers as defined in claim 1 wherein the acrylic compound isN-(2-chloroethyl) methacrylamide.
 4. Method of treating keratinousfibers as defined in claim 1 wherein the polymerization of the vinylcompound is effected under acid conditions in the presence of a peroxidecatalyst and a scavenger for oxygen.
 5. Method of treating keratinousfibers as defined in claim 1 wherein the deposited and thiosulfatereacted polymer is cross-linked with itself and with the keratinousfibers by reaction with cysteine or thioglycolic acid.
 6. Keratinousfibers produced by the method of claim
 1. 7. Keratinous fibers producedby the method of claim 5.